Music can be a bit difficult sometimes as the temptation is to have it too loud, drowning out any speech. Your ears can also get de-sensitised when there's loud music on for a while, so a soft voice after a loud piece of music can sound quieter than the meter might suggest.

What you really have to watch out is that your own ears deceive you, especially with speech. You know what they are saying and will hear the words through sound FX, music and low volume. The listener hears it for the first time, doesn't know what to expect and will sometimes have difficulties where you had none.

One thing I would advise is to play the dialogue track without any other sounds, music etc. Get this one track to balance so that each character is heard at the same level. Some people naturally speak louder than others so listen to each scene and balance them all out use the meters to help you with this. Do this until you feel each character is balanced within each scene and that each scene is balanced with each other. Now add the Foley or other sound effects keeping this in proportion with the rest of the sound you have already recorded.

Now add the music track make sure it does not distract or mask the dialogue, when you are happy you have it right, take it down another couple of Db.

Then test it on other people to see if they can hear what is being said etc.

just to add to the above - also try to listen on as many different systems as possible, different PCs, TVs, sound systems headphones etc. as these are alll likely to respond differently at different frequencies - especially the cheaper one, and let's face it, many people will be listening on cheap PC speakers rather than HiFi (and those same people may well listen on headphones on a different day)

If I clap a right next to your ear, then take a few steps back, it's obviously not going to sound as loud. Your missing distance. You drop something, give it time to hit the ground, then give it distance by lowering the volume.